﻿namespace LeetCodeProject._0001_1000._001_100._61_70._070;

public class Solution
{
    public int ClimbStairs(int n)
    {
        if (n == 0)
            return 1;
        if (n == 1)
            return 1;
        var fn1 = 1;
        var fn2 = 1;
        var fn = 0;
        for (int i = 2; i <= n; i++)
        {
            fn = fn1 + fn2;
            fn1 = fn2;
            fn2 = fn;
        }

        return fn;
    }
}